1. Field of the Invention
The present invention relates to a bicycle. In particular, the invention relates to a transmission mechanism that transmits a driving force that has swung each pedal in the vertical direction.
A bicycle is normally designed so that the user (rider) sits on the saddle, and operates the right pedal and the left pedal (that are connected directly to the free end of a crank arm) with the right foot and the left foot.
Since the structure in which each pedal is connected directly to the free end of the crank arm requires the user to operate each pedal so that each pedal draws a large circle, the user must alternately bend and stretch the right knee and the left knee to a large extent.
2. Description of Related Art
Japanese Utility Model No. 3144223 discloses a bicycle that allows the user to stand and pedal the bicycle by alternately swinging the right pedal and the left pedal in the vertical direction.
However, since the bicycle disclosed in Japanese Utility Model No. 3144223 has a structure in which the front end of the arm that extends forward from the pedal is pivotally attached to the frame, the rear end of the pedal extends diagonally upward, and the upper side of the pedal slopes forward in a state in which the pedal has been moved upward. Therefore, the user cannot operate the pedals as if to walk.
JP-A-2010-260457 discloses a structure in which a pedal that is formed in the shape of the letter “T” is rotatably connected to the free end of a pedal arm through a pedal rotary shaft. However, the structure disclosed in JP-A-2010-260457 lacks stability since the user must hold each pedal horizontally with the bottom of each loot, and requires a complex transmission mechanism using a chain. Therefore, the structure disclosed in JP-A-2010-260457 is not practical.